Keep getting different Salinity readings from different LFS Now what
 

Six months ago I took my swing arm Hydro to a LFS they calibrated it with a refractometer so theoretically it should read corrected from false 1.023 to true 1.025 PPT. Today I took some water to another LFS for tests. With their refractometer it puts my water at 1.027 ??? Like who do I believe should I just leave it alone? My API test kit for ALK is off it reads DKH at 8.0 the LFS Salifert kit shows DKH at 6.1 what the heck??? Could this explain why some of my zoas have mysteriously been closing up from low ALK? One of the other reasons I had tests done is my other API kits for Nitrate and Phosphates are not accurate enough always show zero I hear zoas do better with 0.03 PPM. The LFS Salifert shows my phosphates at zero below 0.03 PPM!!! Should I start feeding more so my poor skinny tang can become fatso without worry?

You should get a refractometer for yourself. They're inexpensive and easy to use.

7.5 vs 6.1 isn't THAT big of a difference for two different kits by two different brands. Probably wouldn't hurt to bring it up a little, but corals that do not build a skeleton don't care about alk quite as much as stony corals do.

If you N and P are both low, and you don't have lots of pest algae, I'd feed to your heart's content. IMHO, with nutrient tests, it's more important to go by how the tank looks rather than what the test kits say. If you don't have pest algae and things look hungry, feeding more is probably a good idea.

Kick over the money for a refractometer and calibration fluid (some come with the fluid).

API test kits are not the best in IMO. I would suggest that you upgrade your kits to some of the higher end kits (worth it in the end).

I would suggest always keeping your tang fat and happy...worry about phosphates afterwards. You can get a reactor to take care of phosphates.

Make me vote number three for buying your own refractometer.

Sounds like there are a few issues to deal with here. First, as others have mentioned, get yourself a refractometer. They cost about the same as your average piece of coral, and are much more reliable and accurate than any swing arm hydrometer. I would stop going to any LFS that is going to "calibrate" your hydrometer. That makes no sense to me. If you don't have an ATO, consider getting one. Once you set one up, you rarely have to worry about salinity -- you can just check it every once in a while to make sure the ATO is keeping everything constant.

In terms of alk, zoas/palys don't really care about low alk. (and 6dKh is not that low to begin with). As Grok mentioned, they don't need alk/calcium to grow because they're soft corals. What's more important is the balance between alk and calcium, because this dictates how stable your system is. All corals, hard or soft, will do much better under stable conditions -- fighting pH alk, phosphate, or almost anything measurable by having their numbers bounce up and down will do more harm than just letting it naturally settle.

Phosphate test kits never tell the true story of what's happening in your tank. For example, if you have a decent fuge with macroalgae, your tests may always have a 0 value, when in reality, there is a presence of phosphate, it's just being taken up by the macroalgae.

Once your water parameters are stable, if you're still having issues, you may want to search for predators such as zoa-eating nudis, or starfish that are disturbing them. And finally, some zoas/palys are just known for melting, and no one knows why.

Have to agree with all the Refracto posts.

My LFS i our area usually use Hydrometer while the ones that do use refractometer calibrate with ro which will in turn show a higher salinity.

What is a good brand refractometer to choose? For top off I have a six gallon bucket with a drip system that works fine for me. I get paranoid with those mechanical top off systems too many horror stories of malfunctions but the magnetic ones that are starting to show up on the market seem promising. I have more then just zoas many of my LPS corals I do believe prefer ALK between 8 and 11 for proper growth. Since I haven't seen any predators on my zoas I'm thinking the issue may be toxic warfare so I started experimenting with seachem seagel. If toxic shock it could take some time for them to fully recover right?

Likewise.

Good advice from D-Nak above.

When the LFS test showed zero phosphates and nitrates should I remove some macro algae and the seagel or can I leave it alone and feed more? Not sure what to do because I've always had problems with patchy red algae growing under blue cloves, rocks and on zoa stalks if my po4 is zero why does this red algae still grow and if zoas need some po4 what do I do?

The Tunze universal osmolator is nearly bullet-proof; no moving parts, and a good bit of safeties built into the programming to ensure that it doesn't flood your tank with freshwater. It will also give you a warning if you forget to fill the ATO reservoir and allow it to go dry.

With regards to a refractometer, the manual ones that are made to work with seawater are pretty much the same. If you get one from a reputable supplier like Marine Depot or Bulk Reef Supply there's little risk. Having said this, you may wish to consider your skill level with instrumentation. If your assessment is that you want something that's nearly foolproof and don't mind a small extra expense to get it, you might want to consider a digital refractometer such as the Milwaukee model. They're automatically temperature compensated, and there's no vernier scale to read (it displays the specific gravity in the test sample in nice big digits).

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